Question

A repeated-measures experiment and an independent-measures experiment both produce t statistics with df = 20. How many individuals participated in each experiment?

Select one:

a. n = 21 for independent-measures and n = 11 for repeated measures

b. n = 22 for independent-measures and n = 21 for repeated measures

c. n = 21 for independent-measures and n = 21 for repeated measures

d. n = 22 for independent-measures and n = 11 for repeated measures

Answer 1

We have t statistic with df=20.

For repeated measure t test, df is given as n-1. Therefore n-1=20, therefore for repeated measure experiment there are 21 individual participated in experiment.

For independent measure t test, df is given as n​​​​​​1+n​​​​​2​-2. Therefore n1+n2-2=20. Therefore for independent measure experiment there are 22 (i.e. n1+n2) individual participated in experiment.

Therefore option b​​​​​​ is correct option. That is, n=22 for independent measure and n=21 for repeated measures.

Thank You.